Optical shutters having offset liquid lenses

Abstract

Electrowetting-actuated optical shutters based on total internal reflection or beam steering. An electrowetting cell contains a conducting liquid and a non-conducting liquid configured to form a liquid-liquid interface extending to the inner walls of the cell. A beam of light is directed to the liquid-liquid interface at an angle near the total internal reflection angle of the interface. Voltage changes the shape of the liquid-liquid interface, without separating it from the inner walls of the cell. Thus, when depending on the voltage applied, the beam is either transmitted in part or substantially totally internal reflected.

What is claimed is: 
     
       1. An optical shutter comprising:
 a first liquid lens having an optical axis; 
 a second liquid lens having an optical axis, wherein the optical axis of the second liquid lens is offset from the optical axis of the first liquid lens; 
 wherein the second liquid lens is spaced apart from the first liquid lens such that there is an air gap between the first liquid lens and the second liquid lens; 
 optical apparatus for shining an input beam of light onto the first liquid lens; and 
 control apparatus for controlling the focal length of each liquid lens; 
 wherein the first liquid lens is configured to focus light on the second liquid lens, away from the optical axis of the second lens and the second liquid lens is configured to act as a prism by changing a tilt of a liquid surface interface within the second lens and thus steering the focused light; 
 wherein the first liquid lens and the second liquid lens are mechanically fixed in place while the optical shutter is in use; and 
 wherein the optical shutter is configured to accomplish an extinction ratio of 60 dB or higher. 
 
     
     
       2. The optical shutter of  claim 1  wherein the first and second liquid lenses are pressure driven lenses. 
     
     
       3. The optical shutter of  claim 1  wherein the first and second liquid lenses are electrowetting cells. 
     
     
       4. The optical shutter of  claim 1  further comprising optics for transmitting or rejecting output light from the second lens based upon output light angle. 
     
     
       5. The optical shutter of  claim 1  configured to achieve extinction ratios greater than 65 dB. 
     
     
       6. The optical shutter of  claim 1  further comprising a barrier configured to transmit or reject output light from the second lens based upon output light angle. 
     
     
       7. The optical shutter of  claim 6  wherein the barrier includes a pinhole configured to selectively transmit light. 
     
     
       8. The optical shutter of  claim 7  wherein the pinhole is on the order of 50 microns or less. 
     
     
       9. The optical shutter of  claim 8  wherein the pinhole is on the order of 20 microns or less. 
     
     
       10. The optical shutter of  claim 6  wherein the input beam of light is on the order of 650 nm. 
     
     
       11. The optical shutter of  claim 6  wherein the input beam of light is on the order of 780 nm. 
     
     
       12. The optical shutter of  claim 6  configured to achieve extinction ratios greater than 65 dB. 
     
     
       13. The optical shutter of  claim 12  configured to achieve extinction ratios greater than 70 dB.